In recent weeks, analysts have time and again invoked history to explain the anti-government, pro-democracy protests sweeping the Arab world from Tunisia to Egypt to Libya. Below are the most common historical precedents they're citing and why these analogies may or may not be appropriate:

THE REVOLUTIONS OF 1989

Background: In 1989, around the time of the Tiananmen Square protests in China, pro-democracy demonstrators overthrew a string of Soviet bloc communist dictatorships in a matter of months through generally non-violent methods. The movement arose in Poland when the opposition group Solidarity rose to power and soon spread to Hungary, East Germany, Czechoslovakia, Bulgaria, and finally Romania, where the unrest turned more violent and the dictator and his wife eventually faced a firing squad. When the dust settled, the Berlin Wall had fallen, the Soviet Union was teetering, and the collapse of Communism was underway.

Similarities: The spontaneous, domino-like way in which today's protests have migrated from one Arab country to another reminds many observers of 1989. German Chancellor Angela Merkel--who grew up in East Germany and entered politics in 1989--claimed that Middle East protesters were "shaking off their fear" just as Eastern Europeans had, while Oxford's Eugene Rogan remarked that "the Poles showed the rest of the region that demonstrations and strikes could challenge the state's ability to repress basic rights, like freedom of speech and free assembly, the same lesson the Tunisians hoped to teach other Arab nations." Adrian Michaels at The Guardian, meanwhile, argues that both revolutions arose out of a climate of political stagnation.

Differences: The Hungarian-American businessman George Soros, who financed opposition movements in Eastern Europe in the lead-up to the revolutions of 1989, points out that Eastern Europeans supported America because it was the Soviet Union's sworn enemy, while demonstrators in the Middle East are suspicious of the U.S. because it is allied with the regimes that are collapsing. James Collins, the U.S. ambassador to the Soviet Union in 1989, told the AP that the Middle East protests "have been uprisings against a sclerotic and out of touch leadership" whereas in in Eastern Europe "the change was much deeper, systemic. It touched the roots of the economy and the way society operated." The Guardian's Timothy Garton Ash, meanwhile, claims that the Middle East movements are less organized and not "led by democratic opposition movements and civil society groups, which in 1989 sustained non-violent discipline, even in the face of provocation, and paved the way to a transition negotiated at round tables."

THE PROTESTS OF 1968

Background: In 1968, a year dominated by the war in Vietnam and the Soviet invasion of Czechoslovakia, student and worker protests convulsed countries ranging from Mexico to Czechoslovakia to the U.S. Perhaps the most high-profile rebellion occurred in France in May, when students swarmed the streets, clashed violently with police, and joined forces with workers, paralyzing the French economy for several weeks. 

Similarities: Michael D. Mosettig at PBS states that the rebellion in France in 1968, like the uprising in Egypt in 2011, was "a largely leaderless revolt of the young, and a government initially in disarray, ending as the middle classes demanded a restoration of order and the government regained control of the situation." Amiel Unger adds that the French students, like the young Egyptian protesters, rose up because they had bleak job prospects after completing their studies. 

Differences: George Friedman at Spero News argues that the 1968 protests "overthrew no regime even temporarily and left some cultural remnants of minimal historical importance." While "the Muslim world will not experience massive regime change as in 1989," he continues, the consequences of the revolts currently underway probably won't be as "ephemeral as 1968." He predicts that "the democracies that eventually arise will produce regimes that will take their bearings from their own culture, which means Islam."

THE REVOLUTIONS OF 1848

Background: In 1848, a revolution in France in 1848 triggered similar uprisings in almost every other country in Europe. Historians attribute the reform movements, which were largely spearheaded by the middle class, to a variety of causes ranging economic hardship to the influence of nationalism, liberalism, and socialism. The revolutions were largely unsuccessful and played out differently in different countries, though were largely unsuccessful regardless of location. In France, for example, protesters ousted the monarch only to see the republic they created crumble shortly thereafter, while the German states failed to unite as they had hoped.

Similarities: The Washington Post's Anne Applebaum argues that that the 1989 revolutions were all about the Soviet Union withdrawing its support of Eastern European dictators, the Middle East protests, like the revolutions of 1848, "are the product of multiple changes--economic, technological, demographic--and have taken on a distinctly different flavor and meaning in each country." She adds that while the revolutions of 1848 failed in the near term, they planted the seeds for change over a longer period. By the end of the 19th century, she notes, Bismarck had united Germany and France had established its Third Republic. She predicts that even if many of the Middle East uprisings fail by 2012, the region may indeed undergo a longer-term transformation, perhaps fueled as much by  negotiation as by popular revolution.

Differences: The Atlantic's Andrew Sullivan argues that 2011, simply put, isn't 1848: "What happens when a backward region has an 1848 in 2011, an era where the rest of the world has already moved way past them--and the people, demographically skewed young, know it via the web and satellite TV? ... We will see some good outcomes and some disastrous ones. But the idea that these tyrants could hang on for ever, given their records and within these global currents is a fantasy."

MIDDLE EAST UPRISINGS AS SOMETHING ENTIRELY NEW

Surveying many of these historical analogues, The Guardian's Timothy Garton Ash concludes that much of what occurred in Egypt was simply new, with no historical precedent:

New in Cairo 2011 is that it is now Arabs and Muslims standing up in large numbers, with courage and (for the most part) peaceful discipline, for basic human dignity, against corrupt, oppressive rulers. New in 2011 is the degree of decentered, networked animation of the demonstrations, so that even the best-informed observers there struggle to answer the question "who is organising this?". New in 2011 is the extraordinary underlying pressure of demography, with half the population in most of these countries being under 25.